Safety helmet



FIG. 1 is a front, top and right-side perspective view of a safety helmet showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a right-side elevational view thereof, the left side being a mirror image; and,

FIG. 5 is a rear elevational view thereof.

The details shown in broken lines form no part of the claimed design. The dot-dash lines represent boundary lines that form no part of the claimed design. 

CLAIM The ornamental design for a safety helmet, as shown and described. 